Radio communication device, base station, method for radio communication, program and radio communication system

ABSTRACT

Provided is a radio communication device including a radio communication section that communicates by radio with a base station that changes a cycle for sending a paging channel to a second cycle in a case where no response is made from the radio communication device responsive to the paging channel sent in accordance with a first cycle, a detecting section that detects a state change of the radio communication device, and a receipt control section that switches a receiving cycle for receiving the paging channel from the first cycle to the second cycle according to a detection result obtained by the detecting section.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.13/978,749, filed Jul. 9, 2013, which is a National Stage ofPCT/JP12/52741, filed Feb. 7, 2012 and is based upon and claims thebenefit of priority from prior Japanese Patent Application No.2011-030657, filed Feb. 16, 2011. The entire contents of each of whichare incorporated herein by reference.

TECHNICAL FIELD

The invention relates to a radio communication device, a base station, amethod for radio communication, a program and a radio communicationsystem.

BACKGROUND ART

Currently, standardization of a 4G radio communication system is underprogress by 3GPP (Third Generation Partnership Project). According tothe 4G, an improvement in maximum communication speed and a qualityimprovement in cell edges can be realized by using technologies such asrelays and carrier aggregation. Further, considerations are given toimproving coverage by introducing base stations other than eNodeB(macro-cell base station), such as NeNB (Home eNodeB, femtocell basestation, compact base station for cell phones) and RRH (Remote RadioHead).

(Paging)

Further, in the LTE, an RRC_Connected mode and an RRC_Idle mode aredefined. The RRC_Connected mode is a state in which a connection isestablished between the UE and the eNodeB, and the UE is capable ofsending an uplink signal and receiving a downlink signal. On the otherhand, the RRC_Idle mode is a state in which power of the UE is saved,and the UE in the RRC_Idle mode monitors the paging channel from theeNodeB, and transitions to the RRC_Connected mode when being called inthe paging channel.

Here, for example, if the UE is called, since the eNodeB sends thepaging channel at a timing that arrives in a cycle called a pagingcycle, the UE of the RRC_Idle mode monitors the paging channel at thepaging cycle. Although power consumption of the UE can be reduced whenthe paging cycle is long, there is a tendency that a delay from when theUE is called to when it responds becomes large. Notably, an intermittentreceiving cycle that is similar to this is disclosed for example inPatent Literature 1.

(MTC)

On the other hand, debates on MTC (Machine Type Communications) are alsoin progress in the 3GPP. The MTC is generally synonymous to M2M (Machineto Machine), and refers to a communication between machines and notdirectly used by a human. The MTC primarily is performed between aserver and a MTC terminal that is not directly used by a human.

For example, as a medical application of the MTC, a case may be assumedin which an MTC terminal collects electrocardiogram information of ahuman, and transmits the electrocardiogram information to a server byusing uplink when a certain trigger condition is met. As anotherapplication of the MTC, a case may be assumed in which a vending machineis caused to function as an MTC terminal, and a server causes thevending machine under management to report sales once every certaincycle (for example, every 30 days).

Such an MTC terminal by way of example has the following features ingeneral, however, not every MTC terminal needs to have all of thefollowing features, and which of the features is to be endowed dependson applications.

Scarce needs to move (Low Mobility)

Transmission of small data (Online Small Data Transmission)

Very low power consumption (Extra Low Power Consumption)

Handled by grouping respective MTCs (Group-based MTC Features)

CITATION LIST Patent Literature

Patent Literature 1: JP H09-83427 A

SUMMARY OF INVENTION Technical Problem

However, as with the UE in the RRC_Idle mode, the paging cycle of aradio communication device that is not connected to a base station wasin an equal interval. Due to this, there has been a problem that adegree of freedom of the paging cycle to be applied to a radiocommunication device is low.

Thus, the invention has been made in view of the above problem, and whatis aimed by the invention is to provide novel and improved radiocommunication device, base station, method for radio communication,program and radio communication system that can flexibly switch thecycle for a communication of the paging channel.

Solution to Problem

According to an embodiment of the present disclosure, there is provideda base station including a radio communication section that communicatesby radio with a radio communication device, and a paging control sectionthat causes the radio communication section to send a paging channel forthe radio communication device in accordance with a first cycle. Thepaging channel includes information indicating a second cycle, and thepaging control section changes a cycle for sending the paging channelfrom the first cycle to the second cycle.

In a case where no response is made from the radio communication deviceresponsive to a paging channel sent in accordance with the second cycle,the paging control section may return the cycle for sending the pagingchannel from the second cycle to the first cycle.

According to another embodiment of the present disclosure, there isprovided a radio communication device including a radio communicationsection that receives a paging channel from a base station in accordancewith a first cycle, and a receipt control section that changes areceiving cycle for receiving the paging channel from the first cycle toa second cycle indicated by the paging channel received by the radiocommunication section.

According to another embodiment of the present disclosure, there isprovided a radio communication device including a radio communicationsection that communicates by radio with a base station that changes acycle for sending a paging channel to a second cycle in a case where noresponse is made from the radio communication device responsive to thepaging channel sent in accordance with a first cycle, a detectingsection that detects a state change of the radio communication device,and a receipt control section that switches a receiving cycle forreceiving the paging channel from the first cycle to the second cycleaccording to a detection result obtained by the detecting section.

The radio communication section may receive a notification indicatingthe first cycle and the second cycle from the base station, and theradio communication device may further include a storage section thatstores the first cycle and the second cycle received by the radiocommunication section.

The receipt control section may switch the receiving cycle between thefirst cycle and the second cycle in an unconnected state with the basestation.

The detecting section may detect a movement of the radio communicationdevice as the state change.

The detecting section may detect that the radio communication device hasmoved to a predetermined location as the state change.

The detecting section may detect a reduction in a remaining power of theradio communication device as the state change.

The radio communication device may have a vending machine function ofselling a product, and the detecting section may detect a change insales by the vending machine function or a reduction in a stock of theproduct as the state change.

A destination of the paging channel may be designated by usingidentification information allotted to the radio communication device,and the identification information used in designating the destinationmay differ in a paging channel sent in accordance with the first cycleand a paging channel sent in accordance with the second cycle.

According to another embodiment of the present disclosure, there isprovided a method for radio communication, the method includingdetecting a state change in the radio communication device, andswitching a receiving cycle for receiving a paging channel from a basestation from a first cycle to a second cycle, the base station beingconfigured to change a cycle for sending the paging channel to a secondtime in a case where no response is made from the radio communicationdevice responsive to the paging channel sent in accordance with thefirst cycle according to a detection result of the state change.

According to another embodiment of the present disclosure, there isprovided a program for causing a computer to function as a radiocommunication device that includes a radio communication section thatcommunicates by radio with a base station that changes a cycle forsending a paging channel to a second cycle in a case where no responseis made from the radio communication device responsive to the pagingchannel sent in accordance with a first cycle, a detecting section thatdetects a state change of the radio communication device, and a receiptcontrol section that switches a receiving cycle for receiving the pagingchannel from the first cycle to the second cycle according to adetection result obtained by the detecting section.

According to another embodiment of the present disclosure, there isprovided a base station including a radio communication section thatcommunicates by radio with a radio communication device, and a pagingcontrol section that changes a cycle for sending a paging channel to asecond cycle in a case where no response is made from the radiocommunication device responsive to the paging channel sent in accordancewith a first cycle.

According to another embodiment of the present disclosure, there isprovided a radio communication system including a radio communicationdevice, and a base station that changes a cycle for sending a pagingchannel to a second cycle in a case where no response is made from theradio communication device responsive to the paging channel sent inaccordance with a first cycle. The radio communication device includes adetecting section that detects a state change of the radio communicationdevice, and a receipt control section that switches a receiving cyclefor receiving the paging channel from the first cycle to the secondcycle according to a detection result obtained by the detecting section.

Advantageous Effects of Invention

As described above, according to the invention, a cycle for acommunication of a paging channel can flexibly be switched.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an explanatory diagram showing an example of a configurationof a radio communication system.

FIG. 2 is an explanatory diagram showing a 4G frame format.

FIG. 3 is an explanatory diagram showing generation of a CCE.

FIG. 4 is an explanatory diagram showing blind decoding.

FIG. 5 is a functional block diagram showing a configuration of a basestation of a first embodiment of the invention.

FIG. 6 is an explanatory diagram showing a specific example of paging bythe base station of the first embodiment of the invention.

FIG. 7 is a functional block diagram showing a configuration of an MTCterminal of the first embodiment of the invention.

FIG. 8 is a sequence diagram showing an operation of the firstembodiment of the invention.

FIG. 9 is a functional block diagram showing a configuration of a basestation of a second embodiment of the invention.

FIG. 10 is an explanatory diagram showing a specific example of pagingby the base station of the second embodiment of the invention.

FIG. 11 is a functional block diagram showing a configuration of an MTCterminal of the second embodiment of the invention.

FIG. 12 is a sequence diagram showing an operation of the secondembodiment of the invention.

FIG. 13 is a functional block diagram showing a configuration of a basestation of a third embodiment of the invention.

FIG. 14 is an explanatory diagram showing a first notification method ofa paging cycle.

FIG. 15 is an explanatory diagram showing a second notification methodof the paging cycle.

FIG. 16 is a functional block diagram showing a configuration of an MTCterminal of the third embodiment of the invention.

FIG. 17 is a sequence diagram showing an operation of the thirdembodiment of the invention.

FIG. 18 is a sequence diagram showing an operation of the thirdembodiment of the invention.

FIG. 19 is a functional block diagram showing a configuration of a basestation of a fourth embodiment of the invention.

FIG. 20 is an explanatory diagram showing a specific example of pagingby the base station of the fourth embodiment of the invention.

FIG. 21 is a functional block diagram showing a configuration of an MTCterminal of the fourth embodiment of the invention.

FIG. 22 is an explanatory diagram showing a switch of a receiving cycleby the MTC terminal of the fourth embodiment of the invention.

FIG. 23 is a sequence diagram showing an operation of the fourthembodiment of the invention.

FIG. 24 is a functional block diagram showing a configuration of a basestation of a fifth embodiment of the invention.

FIG. 25 is an explanatory diagram showing a switch of a paging cycle bythe base station of the fifth embodiment of the invention.

FIG. 26 is an explanatory diagram showing a switch of the paging cycleby the base station of the fifth embodiment of the invention.

FIG. 27 is a sequence diagram showing an operation of the fifthembodiment of the invention.

DESCRIPTION OF EMBODIMENT

Hereinafter, preferred embodiments of the present invention will bedescribed in detail with reference to the appended drawings. Note that,in this specification and the drawings, elements that have substantiallythe same function and structure are denoted with the same referencesigns, and repeated explanation is omitted.

Further, in the description and the drawings, there may also be cases inwhich a plurality of constituent features having substantially the samefunctional configuration is distinguished by adding different alphabetsafter the same reference sign. For example, the plurality of constituentfeatures having substantially the same functional configuration may bedistinguished as MTC terminals 20A, 20B, and 20C. However, in caseswhere the respective one of the plurality of constituent features havingsubstantially the same functional configuration does not need to beparticularly distinguished, only the same reference sign will be given.For example, when the MTC terminals 20A, 20B, and 20C do notparticularly need to be distinguished, each will simply be termed a MTCterminal 20.

Further, the “description of embodiments” will be described inaccordance with the order in the below appendix.

1. Overview of Radio Communication System

-   -   1-1. Overview of radio communication system    -   1-2. Configuration of frame    -   1-3. Paging    -   1-4. Detailed description of paging channel    -   1-5. Blind decoding    -   1-6. Paging expected in MTC

2. Description of Respective Embodiments

-   -   2-1. First embodiment        -   (Configuration of base station of the first embodiment)        -   (Configuration of MTC terminal of the first embodiment)        -   (Operation of the first embodiment)    -   2-2. Second embodiment        -   (Configuration of base station of the second embodiment)        -   (Configuration of MTC terminal of the second embodiment)        -   (Operation of the second embodiment)    -   2-3. Third embodiment        -   (Configuration of base station of the third embodiment)        -   (Configuration of MTC terminal of the third embodiment)        -   (Operation of the third embodiment)    -   2-4. Fourth embodiment        -   (Configuration of base station of the fourth embodiment)        -   (Configuration of MTC terminal of the fourth embodiment)        -   (Operation of the fourth embodiment)    -   2-5. Fifth embodiment        -   (Configuration of base station of the fifth embodiment)        -   (Operation of the fifth embodiment)

3. Conclusion

1. OVERVIEW OF RADIO COMMUNICATION SYSTEM

Currently, standardization of a 4G radio communication system is inprogress in 3GPP. Embodiments of the invention can be adapted to the 4Gradio communication system by way of examples, so an overview of the 4Gradio communication system will be described.

<1-1. Configuration of Radio Communication System>

FIG. 1 is an explanatory diagram showing an example of a configurationof a radio communication system 1. As shown in FIG. 1, the radiocommunication system 1 includes a base station 10, a core networkincluding an MME (Mobility Management Entity) 12, an S-GW (ServingGateway) 14, and a PDN (Packet Data Network)-GW 16, MTC terminals 20,and an MTC server 30.

Embodiments of the invention can be adapted to radio communicationdevices such as the base station 10 and the MTC terminals 20 shown inFIG. 1. Notably, the base station 10 may for example be an eNodeB, arelay node, or a Home eNodeB that is a compact base station for homeuse. Further, the MTC terminals 20 are examples of user equipment (UE),and adaptations to non-MTC terminals such as a cell phone, PC (PersonalComputer), and the like is also possible as embodiments of theinvention.

The base station 10 is a radio base station that communicates with theMTC terminals 20. Although only one base station 10 is shown in FIG. 1,a large number of base stations 10 are connected to the core network inreality. Further, although depiction in FIG. 1 is omitted, the basestation 10 communicates also with other user equipments such as anon-MTC terminal.

The MME 12 is a device that performs controls of settings, opening, andhand-over of a data communication session. The MME 12 is connected tothe base station 10 via an interface called X2.

The S-GW 14 is a device that performs routing and transfer of user data.The PDN-GW 16 functions as a connecting node with an IP service network,and transfers the user data to and from the IP service network.

The MTC terminals 20 are radio terminals specialized for MTC, which is acommunication between machines and is not used directly by a human,which is under discussion in the 3GPP. The MTC terminals 20 performradio communication in accordance with an application with the basestation 10. Further, the MTC terminals 20 perform bidirectionalcommunication with the MTC server 30 via the core network.

For example, as a medical application of the MTC, a case may be assumedin which an MTC terminal 20 collects electrocardiogram information of ahuman, and transmits the electrocardiogram information to the server byusing uplink when a certain trigger condition is met. As anotherapplication of the MTC, a case may be assumed in which a vending machineis caused to function as the MTC terminal 20, and the MTC server 30causes the vending machine under management to report sales once everycertain cycle (for example, every 30 days).

Such an MTC terminal 20 by way of example has the following features ingeneral, however, not every MTC terminal 20 needs to have all of thefollowing features, and which of the features is to be assigned dependson applications.

Scarce needs to move (Low Mobility)

Transmission of small data (Online Small Data Transmission)

Very low power consumption (Extra Low Power Consumption)

Handled by grouping respective MTCs (Group-based MTC Features)

<1-2. Configuration of Frame>

Although details of the aforementioned base station 10 and MTC terminals20 are not decided, they are expected to perform radio communicationconforming to communication between the eNodeB and the UE. Thus,hereinbelow, a radio frame shared between the eNodeB and the UE will bedescribed. Contents to be described hereinbelow can be applied to thecommunication between the base station 10 and the MTC terminals 20.

FIG. 2 is an explanatory diagram showing a 4G frame format. As shown inFIG. 2, a 10 ms radio frame is configured of ten 1 ms sub frames #0 to#9. Further, each 1 ms sub frame is configured of two 0.5 ms slots.Further, each 0.5 ms slot is configured of seven Ofdm symbols.

Notably, the Ofdm symbol is a unit used in a communication scheme of anOFDM (Orthogonal Frequency Division Multiplexing) modulation system, andis a unit by which data processed in one FFT (Fast Fourier Transform) isoutputted.

At a head of each 1 ms sub frame shown in FIG. 2, a control signalcalled a PDCCH (Phy Downlink Control Channel) is added. One Ofdm symbolto three Ofdm symbols at the head of the sub frame are used for atransmission of the PDCCH. That is, there are cases in which one Ofdmsymbol is used for the PDCCH transmission, and there also are cases inwhich three Ofdm symbols are used for the PDCCH transmission.

Notably, a region in the radio frame used for the PDCCH transmission iscalled a control region, and a region in the radio frame used fortransmissions of a PDSCH (Phy Downlink Shared Channel) or a PUSCH (PhyUplink Shared Channel) is called a data region.

<1-3. Paging>

In the LTE, an RRC_Connected mode and an RRC_Idle mode are defined. TheRRC_Connected mode is a state in which a connection is establishedbetween the UE and the eNodeB, and the UE is capable of sending anuplink signal and receiving a downlink signal. On the other hand, theRRC_Idle mode is a state in which power of the UE is saved, and the UEin the RRC_Idle mode monitors the paging channel from the eNodeB, andtransitions to the RRC_Connected mode when being called in the pagingchannel. In the RRC_Idle mode, information of the UE does not exist inthe eNodeB, and in which of tracking areas (paging areas) the UE existsis registered in an MME connected to the eNodeB by a wired connectioncalled an S1-MME interface.

The tracking areas are several tens to hundred eNodeBs that are inproximity, and the MME calls the UE by paging channel (incoming call)from all of the eNodeBs existing in the tracking area of the UE when acall is made to the UE.

Due to this, the UE of the RRC_Idle mode monitors the paging channel byperforming a receiving process at a cycle by which the paging channelmay be sent, and transition to the RRC_Connected mode when the call bythe paging channel is made.

Notably, the UE of the RRC_Idle mode stops clocks and power to a part ofhardware so as to save power other than when it is in the receivingprocess for receiving the paging channels. Further, the UE of theRRC_Idle mode restarts power supply to the hardware before the time whenthe paging channels may be sent from the eNodeBs, performs the receivingprocess of the paging channels, and then again enters the state ofsaving power after the receiving process.

<1-4. Detailed Description of Paging Channel>

In the above described PDCCH, a minimum unit of control information foreach UE is called a CCE (Control Channel Element). In the case ofsending the paging channel to the UE in the PDCCH, the eNodeB sends theCCE including a PI (Paging Indicator) indicating which of resources inthe PDSCH the UE should use to receive the paging channel in accordancewith the PDSCH according to a predetermined cycle. That is, the CCEincludes the receipt permission (grants) that is scheduling information.

In the case where the PI is included in the CCE designated to the UEitself, the UE can acquire information notifying a presence of adownlink signal addressed to the UE itself by receiving the pagingchannel sent on the PDSCH indicated by the PI. Notably, a determinationof whether the CCE is designated to the UE itself or not is performed byblind decoding to be described later.

Here, the PI is inserted in the PDCCH in accordance with thepredetermined cycle when a paging channel for the UE is present (LTE TheUMTS Long Term Evolution, Edited by: Stefania Sesia, Issam Toufik,Matthew Baker, 3.4 Paging, p. 77). This predetermined cycle is called aDRX (Discontinues reception) cycle, or a paging cycle, and is set foreach UE. Such a paging cycle is set by a higher layer signaling such assignaling between the UE and the MME on a NAS (Non-Access Stratum)protocol. Although power consumption of the UE can be reduced when thepaging cycle is long, there is a tendency that a delay from when the UEis called to when it responds becomes large.

<1-5. Blind Decoding>

A P-RNTI for receiving a C-RNTI (Cell Radio Network Temporary Identify)that is an identifier of each UE and the paging channel is allotted toeach UE.

As shown in FIG. 3, the eNodeB adds check bits obtained by a CRC (CyclicRedundancy Check) to the CCE while masking the control information suchas the PI by a P-RNTI, in order to specify the destination of the CCE.Here, the masking may be an exclusive OR (XOR) calculation of thecontrol information and the P-RNTI, or may be a serial coupling of thecontrol information and the P-RNTI.

When the PDCCH configured of a plurality of CCEs is received, the UEextracts the CCE identified by the UE's own P-RNTI by the blinddecoding. Hereinbelow, a specific description will be given withreference to FIG. 4.

FIG. 4 is an explanatory diagram showing the blind decoding. As shown inFIG. 4, the UE performs a CRC check while demasking the respective CCEsby its own P-RNTI as the blind decoding. That is, the UE performs theCRC check of each CCE on the assumption that each CCE is addressed tothe UE itself, and determines a CCE with a normal result is the CCEdesignated to the UE itself.

By such a blind decoding, the UE determines the CCE designated to the UEitself sent from the eNodeB, and can obtain the PI from the CCEdesignated to the UE itself.

<1-6. Paging Expected in MTC>

As described in “1-1. Configuration of radio communication system”, theMTC is required of a super low power consumption. An application by theMTC is expected with frequent data collection and settings once a weekor once a month. For example, an MTC terminal mounted on a vendingmachine is assumed to report sales in accordance with a monthly commandfrom a data collecting center (MTC server).

Accordingly, in the case of performing a setting to read the data of theMTC terminal from the eNodeB once a month, the eNodeB is desired to senda paging (PI+paging channel) at different cycles such as thirty days,thirty-one days, twenty-nine days, and twenty-eight days, depending on adifference of days in each month. Accordingly, although a realization ofacyclic paging cycles is important, in a current LTE that is based onpaging cycles of an equal interval, it is difficult to comply with theacyclic paging cycles.

Notably, there may be a method of performing a long cycled and acyclicpaging in an application layer, however, since sending and receiving ofthe paging channel needs to be performed in a specific sub frame with a1 ms width, such a highly accurate control in the application layer isdifficult.

Further, although it is possible to predeterminedly set to report to theMTC terminal at the end of months in the acyclic pattern such as thirtydays, thirty-one days, twenty-nine days, and twenty-eight days, such apredetermined settings has a defect in that the report is made even incases where the MTC server does not need such a report. Since it isexpected that the number of the MTC terminals will be enormous, acongestion may occur within a network if such unnecessary reports areallowed.

Thus, the embodiments of the invention have been created with the abovecircumstance as a point of concern. According to each of the embodimentsof the invention, the cycle for the communication of the paging channelcan flexibly be switched. Hereinbelow, the respective embodiments ofsuch an invention will be described in detail with reference to thedrawings.

2. DESCRIPTION OF RESPECTIVE EMBODIMENTS 2-1. First Embodiment

Firstly, by referring to FIG. 5 to FIG. 8, the first embodiment of theinvention will be described. According to the first embodiment of theinvention, as will be described below in detail, paging can be usedbased on an acyclic pattern.

(Configuration of Base Station of First Embodiment)

FIG. 5 is a functional block diagram showing a configuration of a basestation 10-1 of the first embodiment of the invention. As shown in FIG.5, the base station 10-1 of the first embodiment of the inventionincludes an antenna 104, a radio communication section 108, a scheduler112, a P-RNTI managing section 116, a paging cycle managing section 121,a storage section 131, a paging control section 141, and a CRC circuit150.

The antenna 104 functions as a sending section that sends a sendingsignal, such as a PDCCH (control signal) and a PDSCH (data signal)supplied from the radio communication section 108, as a radio signal,and a receiving section that supplies a radio signal, which is sent froma radio communication device such as an MTC terminal 20 of the firstembodiment, to the radio communication section 108 by converting theradio signal into an electric receiving signal. Notably, in FIG. 5,although an example in which the base station 10-1 has one antenna isshown, the base station 10-1 may include a plurality of antennas. Inthis case, the base station 10 is capable of realizing a MIMO (MultipleInput Multiple Output) communication, and a diversity communication andthe like.

The radio communication section 108 performs a sending radio processsuch as modulation, DA conversion, filtering, amplification,up-conversion and the like of the sending signal such as PDCCH suppliedfrom the paging control section 141 and PDSCH including user datasupplied from a S-GW 14. Further, the radio communication section 108performs a receiving radio process such as down-conversion, filtering,DA conversion, demodulation and the like of the receiving signalsupplied from the antenna 104.

The scheduler 112 allots resources for data communication to each of theMTC terminals 20. That is, the scheduler 112 allots a resource block inthe PDSCH that each MTC terminal 20 should receive, and allots aresource block in the PUSCH that each MTC terminal 20 should send. Forexample, in a case where a paging channel to an MTC terminal 20 ispresent, the scheduler 116 allots a resource in the PDSCH of a radioframe (10 ms radio frames=ten sub frames) according to a paging cycle ofthe MTC terminal 20 for sending the paging channel to the MTC terminal20.

The P-RNTI managing section 116 manages the allotment of the P-RNTI toeach MTC terminal 20. Notably, the P-RNTI is used to identify adestination of a CCE including a PI.

The paging cycle managing section 121 sets a paging cycle of each MTCterminal 20 during a non-connected period (during an RRC_Idle mode).More specifically, the paging cycle managing section 121 of theembodiment sets the paging cycle for sending the paging channel to a MTCterminal 20-1 of the first embodiment in a combination of two or moredifferent intervals, that is, in an acyclic pattern. For example, thepaging cycle managing section 121 normally sets the paging cycle at a 10radio frame cycle, however, it sets the paging cycle in an acyclicpattern of “3, 5, 2, 9, . . . ”.

Notably, since this acyclic pattern is shared with the MTC terminal20-1, it is not realistic to set unlimited numbers of acyclic patternsas the paging cycle. Due to this, an iteration of the set acyclicpattern may be treated as the paging cycle.

Further, the paging cycle managing section 121 may set the acyclicpattern in accordance with an instruction from a network side, such asan MME 12 or an MTC server 30. For example, in a case where a setting ata cycle that comes at an end of the month such as on 31st, 28th, 31st,and 30th is instructed from the network side, the paging cycle managingsection 121 may set the acyclic pattern by converting the instructedcycles into radio frame units.

The storage section 131 stores the acyclic pattern of each MTC terminal20 set by the paging cycle managing section 121.

The paging control section 141 generates the CCE including the PI in acase where paging information (system information, incoming call and thelike) to the MTC terminal 20-1 is present. More specifically, the pagingcontrol section 141 generates the PI, and the CCE that is obtained bythe CRC circuit 150 by masking the PI by the P-RNTI of the MTC terminal20-1.

Here, the masking may be a calculation of an exclusive OR (XOR) of thePI and the P-RNTI, or may be a serial coupling of the PI and the P-RNTI.Due to this, the MTC terminal 20-1 to which the P-RNTI used in themasking is allotted can be designated as the destination of the PI. TheCCE generated as above is supplied to the radio communication section108, and is mapped in the PDCCH.

Further, the paging control section 141 generates the paging channelincluding paging information. The paging channel is supplied to theradio communication section 108, and is mapped in a resource on thePDSCH indicated by the PI. Notably, the paging information such as theincoming call is supplied via an S1-MME interface from the MME 12 thathandles the control information such as the paging and a handover.

Further, the paging control section 141 of the embodiment controls thepaging (sending of the PI and the paging channel) to the MTC terminal20-1 in the RRC_Idle mode in radio frames in accordance with the acyclicpattern stored in the storage section 131 in connection to the MTCterminal 20-1. Hereinbelow, a more detailed description will be givenregarding this point with reference to FIG. 6.

FIG. 6 is an explanatory diagram showing a specific example of thepaging by the base station 10-1. In a case where the acyclic patternstored in the storage section 131 in connection to the MTC terminal 20-1is “3, 5, 2, 9”, the paging cycle becomes an iteration of the acyclicpattern as shown in FIG. 6. In the case where the paging information forthe MTC terminal 20-1 is present, the paging control section 141 of thebase station 10-1 controls the paging in the radio frames that arrive inaccordance with the acyclic pattern as shown in a square enclosure of“P” in FIG. 6.

As described above, the base station 10-1 of the first embodiment of theinvention can set the acyclic pattern that arrives at the end of monthssuch as 31st (January), 28th (February), 31st (March), 30th (April), . .. , for example, as the paging cycle. Due to this, since the basestation 10-1 can perform the paging only at the end of the month whenthe data report needs to be made from the MTC terminal 20-1, consumptionamounts of radio resources and the MTC terminal 20-1 can be lessenedcompared to a case of predeterminedly setting the MTC terminal 20-1 toreport data each time at the end of the months.

(Configuration of MTC Terminal of the First Embodiment)

Next, with reference to FIG. 7, a configuration of the MTC terminal 20-1of the first embodiment.

FIG. 7 is a functional block diagram showing the configuration of theMTC terminal 20-1 of the first embodiment. As shown in FIG. 7, the MTCterminal 20-1 of the first embodiment includes an antenna 204, a radiocommunication section 208, a receiving cycle control section 221, astorage section 231, a blind decoding section 240, and a CRC circuit250.

The antenna 204 functions as a sending section that sends a sendingsignal, such as a PUSCH (data signal) supplied from the radiocommunication section 208, as a radio signal, and a receiving sectionthat supplies radio signals such as PDCCH and PDSCH, which are sent fromthe base station 10-1, to the radio communication section 208 byconverting the radio signals into electric receiving signals. Notably,in FIG. 7, although an example in which the MTC terminal 20-1 has oneantenna is shown, the MTC terminal 20-1 may include a plurality ofantennas. In this case, the MTC terminal 20-1 is capable of realizingthe MIMO (Multiple Input Multiple Output) communication, and thediversity communication and the like.

The radio communication section 208 performs a sending radio process ofmodulation, DA conversion, filtering, amplification, up-conversion andthe like of the user data supplied from a higher layer. Further, theradio communication section 208 performs a receiving radio process ofdown-conversion, filtering, DA conversion, demodulation and the like ofthe receiving signals supplied from the antenna 204.

The storage section 231 stores various types of information used in thecommunication with the base station 10-1. For example, the storagesection 231 stores the P-RNTI allotted to the MTC terminal 20-1 by theP-RNTI managing section 116 of the base station 10-1, the acyclicpattern set by the paging cycle managing section 121 of the base station10-1 and the like.

The receiving cycle control section 221 is a receipt control sectionthat controls a receiving cycle (DRX cycle) for monitoring the paging inthe RRC_Idle mode. More specifically, the receiving cycle controlsection 221 causes the blind decoding section 240 to perform blinddecoding in accordance with the radio frames complying with the acyclicpattern stored in the storage section 231.

The blind decoding section 240 extracts the CCE identified by the P-RNTIgiven to the MTC terminal 20-1 by the blind decoding when the PDCCH issupplied from the radio communication section 208.

Yet more specifically, the blind decoding section 240 cooperates withthe CRC circuit 250 to perform a CRC check by demasking each CCE by theP-RNTI given to the MTC terminal 20-1. Then, the blind decoding section240 extracts the CCE with a normal result, and supplies the resource onthe PDSCH indicated by the PI described in the CCE as a decoded resultto the radio communication section 208. The radio communication section208 can achieve the paging channel sent from the base station 10-1 bbase station 10-1 by performing the receiving process on the resource onthe PDSCH indicated by the decoded result.

As described above, the MTC terminal 20-1 of the first embodiment canmonitor the paging in accordance with the acyclic pattern set by thebase station 10-1. Notably, in the above, an example in which the basestation 10-1 sets the acyclic pattern and notifies the MTC terminal 20-1is described, however, the MTC terminal 20-1 may set the acyclic patternand notify the acyclic pattern to the base station 10-1.

(Operation of the First Embodiment)

In the above, the configurations of the base station 10-1 and the MTCterminal 20-1 of the first embodiment of the invention was described.Subsequently, by referring to FIG. 8, an operation of the firstembodiment of the invention will be described.

FIG. 8 is a sequence diagram showing an operation of the firstembodiment of the invention. As shown in FIG. 8, in a state in which theMTC terminal 20-1 is operating in the RRC_Connected mode (S302), whenthe base station 10-1 sets the acyclic pattern (S304), the base station10-1 notifies the acyclic pattern to the MTC terminal 20-1 (S306).

The MTC terminal 20-1 returns an ACK to the notification of the acyclicpattern to the base station 10-1 (S308), and stores the acyclic patternin the storage section 231 (S310).

Thereafter, when the MTC terminal 20-1 transitions to the RRC_Idle mode,the receiving cycle control section 221 causes the blind decodingsection 240 to monitor the paging (PI) in accordance with the acyclicpattern stored in the storage section 231 (S312).

On the other hand, when a paging request is supplied from the MME 12 viathe S1-MME interface (S314), the base station 10-1 specifies a timingthat arrives in accordance with the acyclic pattern set in S304 (S316),and performs paging at the specified timing (S318). Here, since the MTCterminal 20-1 is monitoring the paging at the acyclic pattern, thepaging from the base station 10-1 can be achieved.

2-2. Second Embodiment

In the above, the first embodiment of the invention was described. Now,the second embodiment of the invention will be described. According tothe second embodiment of the invention, as will be described in detail,a paging cycle can be switched among a plurality of cycles at a certaintiming.

(Configuration of Base Station of the Second Embodiment)

FIG. 9 is a functional block diagram showing a configuration of a basestation 10-2 of the second embodiment of the invention. As shown in FIG.9, the base station 10-2 of the second embodiment of the inventionincludes an antenna 104, a radio communication section 108, a scheduler112, a P-RNTI managing section 116, a paging cycle managing section 122,a storage section 132, a paging control section 142, and a CRC circuit150. Functions of the antenna 104, the radio communication section 108,the scheduler 112, the P-RNTI managing section 116, and the CRC circuit150 are as described in the first embodiment, so hereinbelow,configurations that differ from the first embodiment will primarily bedescribed.

The paging cycle managing section 122 sets a plurality of cycles forpaging to each MTC terminal 20-2 operating in an RRC_Idle mode, and aswitching timing of the plurality of cycles. For example, the pagingcycle managing section 122 sets a long cycle, a short cycle, and theswitching timing (time, or frame) of the long cycle and the short cycle.The cycle switching timing may be a time to switch the cycle, or a framenumber and the like, or a duration time of the long cycle or the shortcycle, or a continued frame number.

Notably, in a case where the paging cycle managing section 122 setsthree or more cycles, information for determining as to which of thecycles should be switched to at each cycle switching-timing isnecessary. Thus, the paging cycle managing section 122 may set eachcycle switching timing by associating the cycle after the switch.Alternatively, the paging cycle managing section 122 may set a switchingorder of each cycle. By such a configuration, use of cycles of three ormore such as the long cycle, an intermediate cycle, the short cycle andthe like becomes possible.

The storage section 132 stores the plurality of cycles of each MTCterminal 20 set by the paging cycle managing section 122, andinformation indicating the timing to switch the plurality of cycles.

The paging control section 142 controls the paging to the MTC terminal20-2 in the RRC_Idle mode in accordance with radio frames according tothe plurality of cycles and the cycle switching timing stored in thestorage section 132 in connection to the MTC terminal 20-2. Hereinbelow,this feature will be described more specifically with reference to FIG.10.

FIG. 10 is an explanatory diagram showing a specific example of thepaging by the base station 10-2. In a case where the long cycle, theshort cycle, and cycle switching-timings t1, t2 are stored in thestorage section 132 in connection to the MTC terminal 20-2, the pagingcontrol section 142 of the base station 10-2 switches the paging cyclefrom the short cycle to the long cycle at t1 as shown in FIG. 10.Further, the paging control section 142 switches the paging cycle fromthe long cycle to the short cycle at t2.

Then, in a case where paging information to the MTC terminal 20-2 ispresent, the paging control section 142 of the base station 10-2controls the paging by the radio frames that arrive in accordance withthe switching of the long cycle and the short cycle as shown in a squareenclosure of “P” in FIG. 10.

As described above, by for example arranging the short cycle near theend of months, the base station 10-2 of the second embodiment of theinvention can perform paging with less delay from an occurrence of apaging request at the end of months even if days in each month differ.Further, in the second embodiment of the invention, the long cycle, theshort cycle, and the cycle switching-timing can be shared between thebase station 10-2 and the MTC terminal 20-2. Due to this, compared tothe first embodiment, an information amount of signaling from the basestation 10-2 to the MTC terminal 20-2 can more easily be controlled.

(Configuration of MTC Terminal of the Second Embodiment)

Next, the configuration of the MTC terminal 20-2 of the secondembodiment will be described with reference to FIG. 11.

FIG. 11 is a functional block diagram showing the configuration of theMTC terminal 20-2 of the second embodiment. As shown in FIG. 11, the MTCterminal 20-2 of the second embodiment includes an antenna 204, a radiocommunication section 208, a receiving cycle control section 222, astorage section 232, a blind decoding section 240, and a CRC circuit250. Functions of the antenna 204, the radio communication section 208,the blind decoding section 240, and the CRC circuit 250 are as describedin the first embodiment, so hereinbelow, configurations differing fromthe first embodiment will primarily be described.

The storage section 232 stores various types of information used in acommunication with the base station 10-2. For example, the storagesection 232 stores the P-RNTI allotted to the MTC terminal 20-2 by theP-RNTI managing section 116 of the base station 10-2, and the longcycle, the short cycle, the cycle switching-timing and the like that areset by the paging cycle managing section 121 of the base station 10-2.

The receiving cycle control section 222 is a receipt control sectionthat controls a receiving cycle (DRX cycle) for monitoring paging in anRRC_Idle mode. More specifically, the receiving cycle control section222 causes the blind decoding section 240 to perform blind decoding withradio frames in accordance with the long cycle, the short cycle, and thecycle switching-timing stored in the storage section 232.

As described above, the MTC terminal 20-2 of the second embodiment canswitch the receiving cycle among a plurality of cycles at the cycleswitching-timing set by the base station 10-2. Notably, although anexample in which the base station 10-2 sets the cycle switching-timingand notifies the same to the MTC terminal 20-2 is described above, theMTC terminal 20-2 may set the cycle switching-timing and notify the sameto the base station 10-2. Further, in the case where the plurality ofcycles such as the long cycle and the short cycle is shared between thebase station 10-2 and each MTC terminal 20-2 in advance, the basestation 10-2 does not have to notify the long cycle and the short cycle.

(Operation of the Second Embodiment)

In the above, the configurations of the base station 10-2 and the MTCterminal 20-2 of the second embodiment of the invention are described.Next, the operation of the second embodiment of the invention will bedescribed with reference to FIG. 12.

FIG. 12 is a sequence diagram showing the operation of the secondembodiment of the invention. As shown in FIG. 12, in a state where theMTC terminal 20-2 is operating in an RRC_Connected mode (S402), when thebase station 10-2 sets the cycle switching-timing (S404), the basestation 10-2 notifies the cycle switching-timing to the MTC terminal20-2 (S406).

The MTC terminal 20-2 sends an ACK responsive to the notification of thecycle switching-timing to the base station 10-2 (S408), and stores thecycle switching-timing in the storage section 232 (S410). Notably, thebase station 10-2 may notify the plurality of cycles such as the longcycle and the short cycle, in addition to the cycle switching-timing.

Thereafter, when the MTC terminal 20-2 transitions to the RRC_Idle mode,the receiving cycle control section 222 monitors paging in accordancewith the long cycle or the short cycle, and switches the long cycle andthe short cycle at the cycle switching-timing stored in the storagesection 232 (S412).

On the other hand, when the paging request is supplied from an MME 12via an S1-MME interface (S414), the base station 10-2 specifies a timingthat is to arrive in accordance with the long cycle or the short cyclethat is switched at the cycle switching-timing set in S404 (S416), andperforms paging at the specified timing (S418). Here, since the MTCterminal 20-2 is monitoring paging by switching the long cycle and theshort cycle at the same cycle switching-timing as the base station 10-2,the paging from the base station 10-2 can be acquired.

2-3. Third Embodiment

In the above, the second embodiment of the invention was described.Next, the third embodiment of the invention will be described. Accordingto the third embodiment of the invention, as will be described below, apaging cycle can be sequentially updated.

(Configuration of Base Station of the Third Embodiment)

FIG. 13 is a functional block diagram showing the configuration of abase station 10-3 of the third embodiment of the invention. As shown inFIG. 13, the base station 10-3 of the third embodiment of the inventionincludes an antenna 104, a radio communication section 108, a scheduler112, a P-RNTI managing section 116, a paging cycle managing section 123,a storage section 133, a paging control section 143, and a CRC circuit150. Functions of the antenna 104, the radio communication section 108,the scheduler 112, the P-RNTI managing section 116, and the CRC circuit150 are as described in the first embodiment, so hereinbelow,configurations that differ from the first embodiment will primarily bedescribed.

The paging cycle managing section 123 sequentially updates the pagingcycle for paging an MTC terminal 20-3 operating in an RRC_Idle mode. Forexample, the paging cycle managing section 123 updates the paging cycleto a cycle B when the paging cycle is of a cycle A.

The storage section 133 stores the paging cycle (sequentially updatedcycle) sequentially updated by the paging cycle managing section 123.

The paging control section 143 controls the paging to the MTC terminal20-3 in the RRC_Idle mode with radio frames in accordance with thesequentially updated cycle stored in the storage section 133. Here,although the paging cycle updated by the paging cycle managing section123 needs to be notified to the MTC terminal 20-3 as well, as anotification method of the paging cycle, a first notification methoddescribed with reference to FIG. 14 and a second notification methoddescribed with reference to FIG. 15 may be exemplified.

FIG. 14 is an explanatory diagram showing the first notification methodof the paging cycle. As the first notification method, the base station10-3 may notify the paging cycle as below in all of paging channels. Forexample, as shown in FIG. 14, the base station 10-3 may notify the cycleA in a paging channel #11 where the cycle A continues to take placethereafter, and may notify the cycle B in a paging channel #12 where thepaging cycle is to be updated to the cycle 13 thereafter

FIG. 15 is an explanatory diagram showing the second notification methodof the paging cycle. As the second notification method, the base station10-3 may notify the updated paging cycle in the paging channel where thepaging cycle is to be updated thereafter. For example, as shown in FIG.15, the base station 10-3 may not notify the paging cycle in the pagingchannel #11 where the cycle A continues to take place thereafter, andmay notify the cycle B in the paging channel #12 in which the pagingcycle is updated to the cycle B.

As described above, according to the third embodiment of the invention,it is possible to sequentially update the paging cycle related to theMTC terminal 20-3 operating in the RRC_Idle mode responsive to an updaterequest of the paging cycle on a network side including the base station10-3. Further, according to the third embodiment of the invention, sincethere is no need to share an acyclic pattern configured of a pluralityof intervals as in the first embodiment, it is advantageous in theviewpoint of memory resources. Further, especially the secondnotification method is effective in that it can suppress resources forthe notification.

(Configuration of MTC Terminal of the Third Embodiment)

Next, the configuration of the MTC terminal 20-3 of the third embodimentwill be described with reference to FIG. 16.

FIG. 16 is a functional block diagram showing the configuration of theMTC terminal 20-3 of the third embodiment. As shown in FIG. 16, the MTCterminal 20-3 of the third embodiment includes an antenna 204, a radiocommunication section 208, a receiving cycle control section 223, astorage section 233, a blind decoding section 240, and a CRC circuit250. Functions of the antenna 204, the radio communication section 208,the blind decoding section 240, and the CRC circuit 250 are as describedin the first embodiment, so hereinbelow, configurations differing fromthe first embodiment will primarily be described.

The storage section 233 stores various types of information used in acommunication with the base station 10-3. For example, the storagesection 233 stores a P-RNTI allotted to the MTC terminal 20-3 by aP-RNTI managing section 116 of the base station 10-3, and a paging cyclethat is sequentially updated by a paging cycle managing section 121 ofthe base station 10-3, and the like.

The receiving cycle control section 223 is a receipt control sectionthat controls a receiving cycle (DRX cycle) for monitoring paging in anRRC_Idle mode. More specifically, the receiving cycle control section223 causes the blind decoding section 240 to perform blind decoding withradio frames in accordance with the sequentially updated paging cyclestored in the storage section 233.

As described above, the MTC terminal 20-3 of the third embodiment canmonitor the paging in accordance with the paging cycle that issequentially updated by the base station 10-3.

(Operation of the Third Embodiment)

In the above, the configurations of the base station 10-3 and the MTCterminal 20-3 of the third embodiment of the invention were described.Next, the operation of the third embodiment of the invention will bedescribed with reference to FIG. 17.

FIG. 17 is a sequence diagram showing an operation of the thirdembodiment of the invention. As shown in FIG. 17, in a state where theMTC terminal 20-3 is operating in an RRC_Connected mode (S502), when thebase station 10-3 sets the paging cycle (S504), the base station 10-3notifies the paging cycle to the MTC terminal 20-3 (S506).

The MTC terminal 20-3 sends an ACK responsive to the notification of thepaging cycle to the base station 10-3 (S508), and stores the pagingcycle in the storage section 233 (S510).

Thereafter, when the MTC terminal 20-3 transitions to the RRC_Idle mode,the receiving cycle control section 223 monitors paging in accordancewith the paging cycle stored in the storage section 233 (S512).

On the other hand, when the paging request is supplied from an MME 12via an S1-MME interface (S514), the base station 10-3 specifies a timingthat is to arrive in accordance with the paging cycle set in S504(S516). Further, in the case of updating the paging cycle, the basestation 10-3 writes an updated paging cycle in the paging channel(S518). Then, the base station 10-3 performs paging at the timingspecified in S516 by the paging channel in which the updated pagingcycle is written (S520).

When the paging channel in which the updated paging cycle is written isreceived, the MTC terminal 20-3 stores the updated paging cycle in thestorage section 233, and monitors the paging in accordance with theupdated paging cycle (S522).

Here, in the embodiment in which the base station 10-3 sequentiallyupdates the paging cycle and notifies the same to the MTC terminal 20-3as described above, it is important for the base station 10-3 to knowwhether the notification of the updated paging cycle has been correctlyreceived by the MTC terminal 20-3 or not. However, if the MTC terminal20-3 sends a receipt confirmation by an uplink, there is a problem thatsignaling is increased.

Due to this, the base station 10-3 of the embodiment solves the aboveproblem by a method described hereinbelow with reference to FIG. 18.

FIG. 18 is a sequence diagram showing an operation of the thirdembodiment. As shown in FIG. 18, in the case of updating the pagingcycle, the base station 10-3 performs paging by writing the updatedpaging cycle in the paging channel (S532, S534). Thereafter, the basestation 10-3 transitions to the updated paging cycle, and in a casewhere a terminal is called by an incoming call in a first paging channel(S536, S538), it determines presence and absence of a response from theMTC terminal 20-3 to the incoming call (S540).

Here, if the response was not made from the MTC terminal 20-3, a reasonthereof may be due to the MTC terminal 20-3 not being able to correctlyreceive the notification of the updated paging cycle, and the monitoringof the paging is continued in accordance with the paging cycle beforethe update. Thus, in the case where the response to the incoming callwas not made from the MTC terminal 20-3, the base station 10-3 returnsthe paging cycle to the paging cycle before the update (S542). Accordingto such a configuration, the base station 10-3 becomes capable ofperforming the paging at a cycle that is monitored by the MTC terminal20-3.

2-4. Fourth Embodiment

In the above, the first to third embodiments of the invention weredescribed. Next, before describing the fourth embodiment of theinvention, how the fourth embodiment of the invention had been made willbe described.

In a case where a paging cycle of a UE of an RRC_Idle mode is of a longcycle, such as ten days or one month, a state of the UE may change amongthe cycle intervals. However, it had been difficult to change the pagingcycle in accordance with this change in the state. Although performingsignaling for changing the paging cycle by the UE transitioning to anRRC_Connected mode and performing synchronization with an eNodeB may beconsidered, such a method was problematic in that power is consumedtherein.

The fourth embodiment of the invention, and a fifth embodiment to bedescribed below are made by focusing on the above matter. An MTCterminal 20-4 of the fourth embodiment of the invention is capable ofchanging the paging cycle in accordance with the change in the statewhile maintaining the RRC_Idle mode. Hereinbelow, such a fourthembodiment of the invention will be described in detail.

(Configuration of Base Station of the Fourth Embodiment)

FIG. 19 is a functional block diagram showing a configuration of a basestation 10-4 of the fourth embodiment of the invention. As shown in FIG.19, the base station 10-4 of the fourth embodiment of the inventionincludes an antenna 104, a radio communication section 108, a scheduler112, a P-RNTI managing section 116, a paging cycle managing section 124,a storage section 134, a paging control section 144, and a CRC circuit150. Functions of the antenna 104, the radio communication section 108,the scheduler 112, the P-RNTI managing section 116, and the CRC circuit150 are as described in the first embodiment, so hereinbelow,configurations that differ from the first embodiment will primarily bedescribed.

The paging cycle managing section 124 sets a plurality of cycles forpaging to each MTC terminal 20-4 operating in the RRC_Idle mode. Forexample, the paging cycle managing section 124 sets a long cycle and ashort cycle.

The storage section 134 stores information indicating the plurality ofcycles (the long cycle and the short cycle) of each MTC terminal 20-4set by the paging cycle managing section 124.

The paging control section 144 controls the paging to the MTC terminal20-4 in the RRC_Idle mode by radio frames in accordance with each of theplurality of cycles stored in the storage section 134 in connection tothe MTC terminal 20-4. Hereinbelow, this respect will be described indetail with reference to FIG. 20.

FIG. 20 is an explanatory diagram showing a specific example of thepaging by the base station 10-4. The long cycle and the short cycle arestored in the storage section 134 in connection to the MTC terminal20-4, and a case in which the base station 10-4 receives a pagingrequest to the MTC terminal 20-4 from an MME 12 at t4 as shown in FIG.20 will be considered. In this case, as shown in FIG. 20, the pagingcycle managing section 124 of the base station 10-4 performs the pagingto the MTC terminal 20-4 at both a timing in accordance with the shortcycle and a timing in accordance with the long cycle.

(Configuration of MTC Terminal of the Fourth Embodiment)

Next, a configuration of the MTC terminal 20-4 of the fourth embodimentwill be described with reference to FIG. 21.

FIG. 21 is a functional block diagram showing the configuration of theMTC terminal 20-4 of the fourth embodiment. As shown in FIG. 21, the MTCterminal 20-4 of the fourth embodiment includes an antenna 204, a radiocommunication section 208, a receiving cycle control section 224, astorage section 234, a blind decoding section 240, a CRC circuit 250,and a state detecting section 260. Functions of the antenna 204, theradio communication section 208, the blind decoding section 240, and theCRC circuit 250 are as described in the first embodiment, sohereinbelow, configurations differing from the first embodiment willprimarily be described.

The storage section 234 stores various types of information used in acommunication with a base station 10-4. For example, the storage section234 stores a P-RNTI allotted to the MTC terminal 20-4 by a P-RNTImanaging section 116 of the base station 10-4, and a long cycle, a shortcycle and the like set by a paging cycle managing section 124 of thebase station 10-4.

The state detecting section 260 detects a state change of the MTCterminal 20-4. For example, the state detecting section 260 may be avelocity sensor or a GPS that detects a movement of the MTC terminal20-4, or that the MTC terminal 20-4 has moved to a predeterminedposition as the state change.

Further, the state detecting section 260 may detect a decrease in aremaining power of the MTC terminal 20-4 (for example, detect that theremaining power has gone below a threshold) as the state change.Further, in a case where the MTC terminal 20-4 is mounted to anapparatus having a function of a vending machine of products, the statedetecting section 260 may detect change in sales by the vending machinefunction or a decrease in product stocks as the state change.

The receiving cycle control section 224 is a receipt control sectionthat controls a receiving cycle (DRX cycle) for monitoring paging in theRRC_Idle mode. Here, if the state of the MTC terminal 20-4 had not atall changed despite data report (read) order is included in the pagingchannel from the base station 10-4, there may be cases in which usefulinformation cannot be obtained from the MTC terminal 20-4. For example,in a case where the MTC terminal 20-4 is mounted on a vending machinefor canned juice, and the base station 10-4 requests a report of stocksfrom the MTC terminal 20-4 for the purpose of replenishing the cannedjuice, a meaning to have the MTC terminal 20-4 report the stocks issmall if the stocks have not changed at all.

On the other hand, if the state of the MTC terminal 20-4 has changed, itis assumed that a value to have the MTC terminal 20-4 report data bypaging is increased. Due to this, in the case where the state of the MTCterminal 20-4 has changed, it is preferable to make a receiving cycleshort. However, normally, since a connection is not established when theMTC terminal 20-4 is operating in the RRC_Idle mode, it had beendifficult to change the receiving cycle by a communication with the basestation 10-4.

In regards to this feature, the receiving cycle control section 224 ofthe MTC terminal 20-4 of the embodiment switches the receiving cyclebetween the long cycle and the short cycle depending on a detection ofthe state change by the state detecting section 260. Even if the MTCterminal 20-4 one sidedly changes the receiving cycle for paging asabove, since the base station 10-4 of the embodiment performs the pagingto the MTC terminal 20-4 at both the timing in accordance with the shortcycle and the timing in accordance with the long cycle as describedabove with reference to FIG. 20, the MTC terminal 20-4 can receive thepaging from the base station 10-4. Hereinbelow, this feature will bedescribed more specifically with reference to FIG. 22.

FIG. 22 is an explanatory diagram showing switching of the receivingcycle by the MTC terminal 20-4. As shown in FIG. 22, in a case where thestate change is detected by the state detecting section 260 at t3, thereceiving cycle control section 224 of the MTC terminal 20-4 switchesthe receiving cycle from the long cycle to the short cycle. On the otherhand, in a case where the paging request is received from the MME 12 att4, the base station 10-4 performs the paging at both the timing inaccordance with the short cycle and the timing in accordance with thelong cycle. Due to this, the MTC terminal 20-4 can receive the pagingthat is performed at the timing in accordance with the short cycle fromthe base station 10-4 after having switched the receiving cycle.

Here, a specific example of a criterion of the switch of the receivingcycle by the receiving cycle control section 224 will be described. Forexample, in an application for tracking by the MTC terminal 20-4 tomonitor a location where a cargo is, no new information can be obtainedeven if the MTC terminal 20-4 is made to report the location when notransportation of the cargo is taking place. Thus, the MTC terminal 20-4monitors in accordance with the long cycle when there is notransportation of the cargo, and reports the same positionalinformation. On the other hand, when the cargo has moved, the receivingcycle control section 224 of the MTC terminal 20-4 switches thereceiving cycle to the short cycle. Due to this, a response to a callbecomes quicker, and it becomes possible to obtain reports of usefulinformation such as positional information after the transportation orduring the transportation with a shorter response time. Due to the samereason, the receiving cycle control section 224 of the MTC terminal 20-4may switch the receiving cycle to the short cycle when the cargo hasmoved to a specific location.

Further, in a case where remaining power of the MTC terminal 20-4 hasdecreased, the receiving cycle control section 224 of the MTC terminal20-4 may switch the receiving cycle from the short cycle to the longcycle. According to such a configuration, a decreasing speed of theremaining power of the MTC terminal 20-4 can be suppressed.

Further, in a case where sales by the vending machine function isobtained, or in a case where stocks of the products becomes short, thereceiving cycle control section 224 of the MTC terminal 20-4 may switchthe receiving cycle from the long cycle to the short cycle. According tosuch a configuration, the network side can acquire useful informationwith less delay.

(Operation of the Fourth Embodiment)

In the above, the configurations of the base station 10-4 and the MTCterminal 20-4 of the fourth embodiment of the invention were described.Next, the operation of the fourth embodiment of the invention will bedescribed with reference to FIG. 23.

FIG. 23 is a sequence diagram showing an operation of the fourthembodiment of the invention. As shown in FIG. 23, in the state in whichthe MTC terminal 20-4 is operating in the RRC_Connected mode (S602), thebase station 10-4 sets the long cycle and the short cycle (S604), andnotifies the long cycle and the short cycle to the MTC terminal 20-4(S606).

The MTC terminal 20-4 returns an ACK to the base station 10-4 inresponse to the notification of the long cycle and the short cycle(S608), and stores information indicating the long cycle and the shortcycle in the storage section 234 (S610).

Thereafter, when the MTC terminal 20-4 transitions to the RRC_Idle mode,the receiving cycle control section 224 monitors paging in accordancewith the long cycle stored in the storage section 234 (S612). Notably,the receiving cycle control section 224 may set the receiving cycle justafter having transitioned to the RRC_Idle mode in the short cycle.

On the other hand, when the paging request is supplied from the MME 12via the S1-MME interface (S614), the base station 10-4 specifies atiming in accordance with the long cycle and a timing in accordance withthe short cycle (S616), and performs paging at both of the timings(S618, S620). Here, since the MTC terminal 20-4 is monitoring the pagingin accordance with the long cycle, it can acquire the paging at thetiming according to the long cycle (S620).

Thereafter, in the case where the state change is detected by the statedetecting section 260 (S622), the receiving cycle control section 224 ofthe MTC terminal 20-4 switches the receiving cycle from the long cycleto the short cycle (S624).

Then, when the paging request is supplied from the MME 12 via the S1-MMEinterface (S626), the base station 10-4 specifies the timing inaccordance with the long cycle and the timing in accordance with theshort cycle (S628), and performs the paging at both of the timings(S630, S632). Here, since the MTC terminal 20-4 is monitoring the pagingin accordance with the short cycle, it can acquire the paging at thetiming according to the short cycle (S630).

2-5. Fifth Embodiment

In the above, the fourth embodiment of the invention was described.Next, the fifth embodiment of the invention will be described. The fifthembodiment of the invention is made in view of the same problem as thefourth embodiment of the invention, and an MTC terminal 20-5 of thefifth embodiment of the invention is capable of changing a paging cyclein accordance with a state change while maintaining an RRC_Idle mode.Hereinbelow, such a fifth embodiment of the invention will be describedin detail. Notably, functional blocks of the MTC terminal 20-5 of thefifth embodiment can be configured substantially identical to thefunctional blocks of the MTC terminal 20-4 of the fourth embodiment, soa detailed description thereof will be omitted.

(Configuration of Base Station of the Fifth Embodiment)

FIG. 24 is a functional block diagram showing the configuration of abase station 10-5 of the fifth embodiment of the invention. As shown inFIG. 24, the base station 10-5 of the fifth embodiment of the inventionincludes an antenna 104, a radio communication section 108, a scheduler112, a P-RNTI managing section 116, a paging cycle managing section 125,a storage section 135, a paging control section 145, and a CRC circuit150. Functions of the antenna 104, the radio communication section 108,the scheduler 112, the P-RNTI managing section 116, and the CRC circuit150 are as described in the first embodiment, so hereinbelow,configurations that differ from the first embodiment will primarily bedescribed.

The paging cycle managing section 125 sets a plurality of cycles forpaging each MTC terminal 20-5 operating in an RRC_Idle mode. Forexample, the paging cycle managing section 125 sets a long cycle and ashort cycle.

The storage section 135 stores information indicating the plurality ofcycles (long cycle and short cycle) of each MTC terminal 20-5 set by thepaging cycle managing section 125.

The paging control section 145 controls the paging to the MTC terminal20-5 in the RRC_Idle mode by radio frames in accordance with one of theplurality of cycles stored in the storage section 135 in connection tothe MTC terminal 20-5.

Here, the MTC terminal 20-5 of the fifth embodiment switches a receivingcycle for the paging according to the state change of the MTC terminal20-5, similar to the fourth embodiment. On the other hand, a basestation 10-5 performs paging in accordance with a cycle before theswitch by the MTC terminal 20-5, even after the switch of the receivingcycle by the MTC terminal 20-5. Due to this, since the MTC terminal 20-5cannot receive the paging, the base station 10-5 cannot receive aresponse to the paging from the MTC terminal 20-5.

Thus, in a case where the response to the paging cannot be obtained fromthe MTC terminal 20-5, the base station 10-5 determines that the MTCterminal 20-5 has switched the receiving cycle, and switches the pagingcycle for the MTC terminal 20-5. Hereinbelow, this feature will bedescribed specifically with reference to FIG. 25 and FIG. 26.

FIG. 25 is an explanatory diagram showing a switch of the paging cycleby the base station 10-5. As shown in FIG. 25, in a case where the MTCterminal 20-5 is monitoring the paging in the long cycle, and when thebase station 10-5 sends a paging #21 in accordance with the long cycle,the MTC terminal 20-5 receives this paging #21.

Thereafter, when the MTC terminal 20-5 switches to the short cycle bythe state change at t5, the MTC terminal 20-5 can no longer receive apaging #22 that the base station 10-5 sends in accordance with the longcycle. Due to this, the paging control section 145 of the base station10-5 determines that the MTC terminal 20-5 has switched the receivingcycle since a response to the paging #22 cannot be obtained, switchesthe paging cycle to the short cycle and sends a paging #22′. Since theMTC terminal 20-5 is monitoring the paging in accordance with the shortcycle, it is possible to receive this paging #22′.

Accordingly, in the case where the base station 10-5 switches the pagingcycle from the long cycle to the short cycle, although time from beingcalled to the response will not be shortened, since the paging is sentin accordance with the long cycle until when it is necessary, there isan advantage in that resources for the paging can be saved.

Notably, normally a plurality of MTC terminals 20-5 belongs to oneP-RNTI. Further, the plurality of MTC terminals 20-5 belonging to thesame P-RNTI may include both MTC terminals 20-5 operating in the longcycle and MTC terminals 20-5 operating in the short cycle. Due to this,the base station 10-5 may perform the paging to different MTC terminals20-5 by using the same P-RNTI at both the timing in accordance with theshort cycle and the timing in accordance with the long cycle.

Further, in a case where each of timings that arrives in accordance withthe long cycle is identical to the timing that arrives in accordancewith the short cycle, the MTC terminal 20-5 can receive the paging sentin accordance with the long cycle even after having switched to theshort cycle in regards to the timing. However, in this case, it becomesdifficult for the base station 10-5 to determine the switch in thereceiving cycle of the MTC terminal 20-5.

Thus, the base station 10-5 may allot a P-RNTI for the long cycle and aP-RNTI for the short cycle to each MTC terminal 20-5, and may use theP-RNTI for the long cycle upon performing the paging in accordance withthe long cycle, and the P-RNTI for the short cycle upon performing thepaging in accordance with the short cycle. Further, the MTC terminal20-5 may perform blind decoding using the P-RNTI for the long cycle uponmonitoring the paging in the long cycle, and perform the blind decodingusing the P-RNTI for the short cycle upon monitoring the paging in theshort cycle. According to such a configuration, it becomes possible forthe base station 10-5 to determine the switch in the receiving cycle ofthe MTC terminal 20-5 at a high accuracy.

In the above, although an example in which the paging cycle (receivingcycle) is switched from the long cycle to the short cycle was described,as will be described with reference to FIG. 26, a switch from the shortcycle to the long cycle is also possible.

FIG. 26 is an explanatory diagram showing the switch of the paging cycleby the base station 10-5. As shown in FIG. 26, in the case where thepaging is monitored in the short cycle, the MTC terminal 20-5 receives apaging #31 when the base station 10-5 sends the paging #31 in accordancewith the short cycle.

Thereafter, when the MTC terminal 20-5 switches the receiving cycle tothe long cycle at t6 by the state change, a paging #32 that the basestation 10-5 sends in accordance with the short cycle can no longer bereceived by the MTC terminal 20-5. Due to this, the paging controlsection 145 of the base station 10-5 determines that the MTC terminal20-5 has switched the receiving cycle since a response to the paging #32cannot be obtained, switches the paging cycle to the long cycle andsends a paging #32′. Since the MTC terminal 20-5 is monitoring thepaging in accordance with the long cycle, it is possible to receive thispaging #32′.

Accordingly, by the MTC terminal 20-5 switching the receiving cycle fromthe short cycle to the long cycle, consumed power of the MTC terminal20-5 can be reduced. Notably, in this case, although time from beingcalled to responding becomes long, an undesirable influence therefrom issmall since the MTC terminal 20-5 switches the monitoring cycle of thepaging to the long cycle in cases where no problem is expected even ifthe response is delayed.

(Operation of the Fifth Embodiment)

In the above, the configurations of the base station 10-5 and the MTCterminal 20-5 of the fifth embodiment of the invention were described.Next, the operation of the fifth embodiment of the invention will bedescribed with reference to FIG. 27.

FIG. 27 is a sequence diagram showing an operation of the fifthembodiment of the invention. As shown in FIG. 27, in a state where theMTC terminal 20-5 is operating in the RRC_Connected mode (S702), thebase station 10-5 sets the long cycle and the short cycle (S704), andnotifies the long cycle and the short cycle to the MTC terminal 20-5(S706).

The MTC terminal 20-5 returns an ACK responsive to the notification ofthe long cycle and the short cycle to the base station 10-5 (S708), andstores information indicating the long cycle and the short cycle in thestorage section 234 (S710).

Thereafter, when the MTC terminal 20-5 transitions to the RRC_Idle mode,the receiving cycle control section 224 monitors the paging inaccordance with the long cycle stored in the storage section 234 (S712).Notably, the receiving cycle control section 224 may set the receivingcycle just after having transitioned to the RRC_Idle mode in the shortcycle.

On the other hand, when a paging request is supplied from the MME 12 viathe S1-MME interface (S714), the base station 10-5 specifies a timing inaccordance with the long cycle (S716), and performs the paging at thespecified timing (S718). Here, since the MTC terminal 20-5 is monitoringthe paging in accordance with the long cycle, the paging from the basestation 10-5 can be acquired (S720).

Thereafter, in a case where the state change is detected by the statedetecting section 260 (S720), the receiving cycle control section 224 ofthe MTC terminal 20-5 switches the receiving cycle from the long cycleto the short cycle (S722).

Then, when the paging request is supplied from the MME 12 via the S1-MMEinterface (S724), the base station 10-5 specifies a timing in accordancewith the long cycle (S726), and performs the paging at the specifiedtiming (S728). However, since the MTC terminal 20-5 is monitoring thepaging in accordance with the short cycle, the base station 10-5 cannotacquire the response to this paging.

Due to this, the paging control section 145 of the base station 10-5determines that the MTC terminal 20-5 has switched the receiving cycle,and performs the paging by switching the paging cycle to the short cycle(S730, S732). Here, since the MTC terminal 20-5 is monitoring the pagingin accordance with the short cycle, the paging sent in S732 can beacquired.

3. CONCLUSION

As described above, according to the first to third and fifthembodiments of the invention, it becomes possible for the base station10 to perform the paging by switching the plurality of cycles. Forexample, the base station 10-1 of the first embodiment can perform thepaging in accordance with the acyclic pattern in which the end of themonths such as 31st, (January), 28th (February), 31st (March), 30th(April), and so on arrives.

Further, since the base station 10-4 of the fourth embodiment of theinvention performs the paging in the plurality of cycles, the MTCterminal 20-4 of the fourth embodiment can switch the receiving cycle ofthe paging for example in accordance with the state change of the MTCterminal 20-4 without having have to communicate with the base station10-4 in advance.

Notably, although preferred embodiments of the invention have beendescribed in detail with reference to the attached drawings, theinvention is not limited to these examples. A person skilled in the artfinds various alterations and modifications within the scope of theappended claims, and it should be understood that they will naturallycome under the technical scope of the present invention.

For example, it is possible to combine the technical matters of aplurality of embodiments among the first to fifth embodiments of theinvention. More specifically, combinations of the technical matters ofthe fourth or fifth embodiment and the technical matters of the first orsecond embodiment also belong to the technical scope of the invention.For example, in the case of combining the fourth embodiment and thefirst embodiment, the base station 10 may retain a plurality of sets ofacyclic patterns and perform the paging at timing s in accordance withrespective ones of the plurality of sets of acyclic patterns, and theMTC terminal 20 may switch the acyclic pattern for monitoring the pagingin accordance with the state change.

For example, respective steps in the processes by the base station 10and the MTC terminal 20 in the description do not necessarily beperformed in chronological orders as described in sequence diagrams. Forexample, the respective steps in the processes by the base station 10and the MTC terminal 20 may be performed in orders different from theorders described the in sequence diagrams, or may be performed inparallel.

Further, computer programs for causing hardware such as CPUs, ROMs, andRAMs installed in the base station 10 and the MTC terminal 20 to exhibitsimilar functions as the respective configurations of the base station10 and the MTC terminal 20 may be produced. Further, storage mediastoring such computer programs may also be provided.

REFERENCE SIGNS LIST

-   10 Base station-   12 MME-   14 S-GW-   20 MTC terminal-   104, 204 Antenna-   108, 208 Radio communication section-   112 Scheduler-   116 P-RNTI managing section-   121 to 125 Paging cycle managing section-   131 to 135, 231 to 234 Storage section-   141 to 145 Paging control section-   150 CRC circuit-   221 to 224 Receiving cycle control section-   240 Blind decoding section-   250 CRC circuit-   260 State detecting section

The invention claimed is:
 1. A base station comprising: circuitry, whichincludes a processor, configured to communicate with a radiocommunication device, and send a paging channel for the radiocommunication device in accordance with a first paging cycle, the pagingchannel including information indicating a second paging cycle in a caseof updating the first paging cycle, and change a paging cycle forsending a next paging channel from the first paging cycle to the secondpaging cycle; and memory that stores the first paging cycle and thesecond paging cycle.
 2. The base station according to claim 1, whereinin a case where no response is received from the radio communicationdevice responsive to the next paging channel sent in accordance with thesecond paging cycle, the circuitry returns the paging cycle for sendingthe paging channel from the second paging cycle to the first pagingcycle.
 3. A radio communication device comprising: circuitry configuredto detect a state change of the radio communication device, and switch apaging receiving cycle for receiving a paging channel from a firstpaging cycle to a second paging cycle based on a detection resultobtained using the circuitry; and memory configured to store the firstpaging receiving cycle and the second paging receiving cycle, whereinthe circuitry receives a notification indicating the first paging cycleand the second paging cycle from a base station.
 4. The radiocommunication device according to claim 3, wherein the circuitryswitches the paging receiving cycle between the first paging cycle andthe second paging cycle in an unconnected state with the base station.5. The radio communication device according to claim 4, wherein thecircuitry detects a movement of the radio communication device as thestate change.
 6. The radio communication device according to claim 5,wherein the circuitry detects that the radio communication device hasmoved to a predetermined location as the state change.
 7. The radiocommunication device according to claim 6, wherein the circuitry detectsa reduction in a remaining power of the radio communication device asthe state change.
 8. The radio communication device according to claim4, wherein the radio communication device has a vending machine functionof selling a product, and wherein the circuitry detects a change insales by the vending machine function or a reduction in a stock of theproduct as the state change.
 9. The radio communication device accordingto claim 4, wherein a destination of the paging channel is designatedusing identification information allotted to the radio communicationdevice, and wherein the identification information used in designatingthe destination differs in a paging channel sent in accordance with thefirst paging cycle and a paging channel sent in accordance with thesecond paging cycle.
 10. A method for radio communication, the methodcomprising: receiving, using circuitry, a paging channel for a radiocommunication device in accordance with a first paging cycle, the pagingchannel including information indicating a second paging cycle in a caseof updating the first paging cycle; and changing, using the circuitry, apaging receiving cycle for receiving a next paging channel from thefirst paging cycle to the second paging cycle, wherein the circuitryreceives a notification indicating the first paging cycle and the secondpaging cycle from a base station.
 11. A non-transitory computer-readablestorage medium including a program stored thereon, which, when executedby a computer, causes the computer to perform a radio communicationprocessing method, the method comprising: transmitting a paging channelfor the radio communication device in accordance with a first pagingcycle, the paging channel including information indicating a secondpaging cycle in a case of updating the first paging cycle; and switchinga paging cycle for sending a paging channel to the second paging cyclein a case where no response is made from the radio communication deviceresponsive to the paging channel sent in accordance with the firstpaging cycle.
 12. A base station comprising: circuitry configured tocommunicate with a radio communication device, and transmit a pagingchannel for the radio communication device in accordance with a firstpaging cycle, the paging channel including information indicating asecond paging cycle in a case of updating the first paging cycle, andchange a paging cycle for sending a paging channel from the first pagingcycle to the second paging cycle in a case where no response is madefrom the radio communication device responsive to the paging channelsent in accordance with the first paging cycle; and memory to store oneor more of the first paging cycle and the second paging cycle.
 13. Aradio communication system comprising: a radio communication device; anda base station that changes a cycle for sending a paging channel from afirst paging cycle to a second paging cycle in a case where no responseis made from the radio communication device responsive to the pagingchannel sent in accordance with the first paging cycle, wherein theradio communication device includes: circuitry configured to receive apaging channel for the radio communication device in accordance with thefirst paging cycle, the paging channel including information indicatingthe second paging cycle in a case of updating the first paging cycle;and memory configured to store a first paging receiving cycle and asecond paging receiving cycle based on the first paging cycle and thesecond paging cycle, respectively.